Neuroform Atlas Research Articles

An Alternative Rescue Procedure for Neuroform Atlas® Withdrawal During Deployment: A Report of Two Cases

An Alternative Rescue Procedure for Neuroform Atlas® Withdrawal During Deployment: A Report of Two Cases

Anterior circulation location-specific results for stent-assisted coiling – carotid versus distal aneurysms: 1-year outcomes from the Neuroform Atlas Stent Pivotal Trial

BackgroundThe Neuroform Atlas Stent System is an established treatment modality for unruptured anterior and posterior circulation intracranial aneurysms. Location-specific results are needed to guide treatment decision-making. However, it is unclear...

Safety and effectiveness of Neuroform Atlas stent-assisted coil embolization for ruptured intracranial aneurysms.

The treatment outcomes of ruptured intracranial aneurysms using the Neuroform Atlas stent were evaluated. This study represents a retrospective review that included patients who underwent endovascular treatment for ruptured aneurysms at a single institution. Between January 2018 and September 2022, endovascular treatments including simple coiling or Neuroform Atlas stent-assisted coil embolization were performed in 191 patients with ruptured intracranial aneurysms. Intraprocedural rupture was observed in 11 (8.7%) patients in the Simple Coiling (SC) group, which was slightly higher than that in 4 (6.3%) patients in the Neuroform Atlas stent-assisted coiling (NASAC) group (p=0.241). However, Thromboembolic event (TEE) was slightly more prevalent in the NASAC group, with 4 (6.3%) cases as compared to the 5 (3.9%) cases in the SC group (p=0.235). The retreatment rate was slightly higher in the SC group, with 19 (26.4%) patients as compared to the 10 patients (22.2%) in the NASAC group (p=0.342). The use of the Neuroform Atlas stent (NAS) for ruptured aneurysms might be safe and effective.

Single Neuroform Atlas stent: a reliable approach for treating complex wide-neck bifurcated aneurysms.

Treating wide-neck bifurcated cerebral aneurysms (WNBAs) using various techniques and new devices has shown favorable outcomes. However, endovascular coiling can be technically challenging when the aneurysm neck is incorporated into the parent vessel. Furthermore, although recent research has reported favorable outcomes of Neuroform Atlas stent (NAS)-assisted coiling, broad inclusion criteria have hampered precise evaluations of their effectiveness and safety for treating complex WNBAs. Therefore, this study evaluated whether the use of a single NAS is a safe and effective approach for treating complex WNBAs. We treated 76 complex WNBAs (unruptured, n = 49; ruptured, n = 27) using single NAS-assisted coil embolization and retrospectively analyzed the clinical and angiographic outcomes. In a cohort of 68 patients (mean age, 58.3 ± 11.6 years; males n = 20, 29.4%; females, n = 48, 70.6%), 76 stents were successfully delivered to the target aneurysms, yielding a technical success rate of 98.6%. Complete occlusion was evident in 59 (77.6%) of 76 aneurysms, with neck remnants found in 16 (21.1%) and partial occlusion in 1 (1.3%). Treatment-related morbidities comprised one branch occlusion and one parenchymal hemorrhage. However, no new neurological symptoms of unruptured aneurysms were evident at discharge. The outcomes of 20 of the 27 ruptured aneurysms were favorable (Glasgow Outcome Scale scores of 4 or 5) at the final follow-up assessment (mean 12.2 [6-29] months), except for one initial subarachnoid hemorrhage. Post-treatment angiography revealed complete occlusion in 89.1%, neck remnants in 7.8%, and incomplete occlusion in 3.1% of the aneurysms. Approximately 88.2% of the patients were assessed at least once by follow-up diagnostic or magnetic resonance angiography (mean, 12.5 ± 4.3 [range, 6-29] months), with five (7.8%) minor and two (3.1%) major recurrences. A single NAS is safe and effective for treating WNBAs incorporated into parent vessels.

Use of the Neuroform Atlas Stent or LVIS Jr Stent for Treatment of Unruptured Intracranial Aneurysms in Parent Arteries of

The Neuroform Atlas stent and the LVIS Jr stent are intracranial microstent systems for the treatment of wide-neck intracranial aneurysms. Hence, this study aimed to compare the efficacy and safety of the Neuroform Atlas stent and the LVIS Jr stent for the treatment of unruptured intracranial aneurysms in parent arteries of <2 mm in diameter. From March 2022 to April 2023, the clinical and imaging data of 135 patients with unruptured intracranial aneurysms treated with stent-assisted coiling using the Neuroform Atlas or LVIS Jr stent in parent arteries of <2 mm in diameter were retrospectively analyzed. Stent apposition was evaluated by high-resolution conebeam CT (HR-CBCT). Immediate aneurysm-embolization attenuation and occlusion at 6-month follow-up were evaluated using 2D DSA and the modified Raymond-Roy classification. Adverse events were recorded. Multivariate logistic regression analysis was undertaken to determine the independent factors affecting incomplete stent apposition. One hundred thirty-five patients (135 aneurysms) underwent stent-assisted coiling (66 Neuroform Atlas stents and 69 LVIS Jr stents). Intraoperative HR-CBCT showed that 1 Neuroform Atlas stent and 11 LVIS Jr stents had incomplete stent apposition at the aneurysm neck (P < .05). Perioperative complications occurred in 3 cases (2.22%). These comprised 2 cases of neurologic complications (1 case of distal intracranial vascular embolism and 1 case of cerebral parenchymal hemorrhage) and 1 case of severe postprocedural gastrointestinal hemorrhage. DSA follow-up showed 3 cases of aneurysm recurrence in the LVIS Jr group. Multivariate regression analysis showed that a stent angle of ≥75° (OR, 23.963; P = .005) or a parent artery diameter mismatch ratio of ≥1.25 (OR, 8.043; P = .037) were risk factors for incomplete stent apposition, especially for the LVIS Jr stent (OR, 20.297; P = .015). The Neuroform Atlas stent and LVIS Jr stent are efficacious in the treatment of unruptured intracranial aneurysms in parent arteries of <2 mm in diameter. Apposition of the LVIS Jr stent was worse than in the Neuroform Atlas stent at the neck of some aneurysms.

Neuroform atlas stent treatment for 533 intracranial aneurysms in a large Chinese cohort: complication risk factor analysis

BackgroundThe newest generation of Neuroform Atlas stent™ (Stryker, Fremont, California) represents a recent advance of cerebral laser-cut microstents for the treatment of intracranial wide-necked aneurysms, and postoperative complications have been observed among Western patients. We assessed predictors of complications, morbidity, and unfavourable outcomes in a large cohort of patients with aneurysms that were treated with Neuroform Atlas stents in China.MethodsThis retrospective study included subjects who were treated with Atlas stents in China from November 2020 to January 2022.ResultsA total of 522 consecutive patients (mean age, 58.9 ± 9.9 years; female, 65.3% [341/522]) with 533 aneurysms were included in the study. In the early postoperative period, the neurological morbidity rate was 7.3% (38/522), the ischaemic stroke rate was 5.0% (26/522), the aneurysm rupture subarachnoid haemorrhage rate was 2.3% (12/522), and the mRS score deterioration rate was 5.4% (28/522). The mortality rate was 0.8% (4/522) in the postoperative period. The rate of neurological morbidity during the follow-up period was 1.2% (6/486). In the multifactor prediction analysis, cerebral infarction, Hunt–Hess grade (3–5), procedure duration, stent length and coil protrusion into the parent artery were found to be independent predictors of neurologic morbidity. The procedure duration, stent length and coil protrusion into the parent artery were found to be independent predictors of mRS score deterioration.ConclusionsThe incidence of SCA (stent-assisted coiling)-related complications with the Atlas stent in this study population was comparable to that in Western populations. We identified the procedure duration and stent length as novel independent predictors of SCA-related ischaemic stroke, neurological morbidity, and mRS score deterioration among the Chinese population.

The white-collar sign after Neuroform Atlas stent-assisted coil embolization of unruptured intracranial aneurysms.

Although stent-assisted technique is expected to help provide a scaffold for neointima formation at the orifice of the aneurysm, not all aneurysms treated with stent-assisted technique develop complete neointima formation. The white-collar sign (WCS) indicates neointimal tissue formation at the aneurysm neck that prevents aneurysm recanalization. The aim of this study was to explore factors related to WCS appearance after stent-assisted coil embolization of unruptured intracranial aneurysms (UIAs). A total of 59 UIAs treated with a Neuroform Atlas stent were retrospectively analyzed. The WCS was identified on digital subtraction angiography (DSA) 1year after coil embolization. The cohort was divided into WCS-positive and WCS-negative groups, and possible predictors of the WCS were explored using logistic regression analysis. The WCS appeared in 20 aneurysms (33.9%). In the WCS-positive group, neck size was significantly smaller (4.2 (interquartile range (IQR): 3.8-4.6) versus 5.4 (IQR: 4.2-6.8) mm, p = .006), the VER was significantly higher (31.8% (IQR: 28.6%-38.4%) versus 27.6% (IQR: 23.6%-33.8%), p = .02), and the rate of RROC class 1 immediately after treatment was significantly higher (70% vs 20.5%, p < .001) than in the WCS-negative group. On multivariate analysis, neck size (odds ratio (OR): 0.542, 95% confidence interval (CI): 0.308-0.954; p = .03) and RROC class 1 immediately after treatment (OR: 6.99, 95% CI: 1.769-27.55; p = .006) were independent predictors of WCS appearance. Smaller neck size and complete occlusion immediately after treatment were significant factors related to WCS appearance in stent-assisted coil embolization for UIAs using the Neuroform Atlas stent.

Comparison of the safety and efficacy of Neuroform Atlas stent deployed via Gateway balloon catheter and microcatheter for the treatment of intracranial stenosis

ObjectiveThis study aimed to compare the safety and efficacy of the Atlas stent released by the Gateway catheter and microcatheter in the treatment of intracranial stenosis (IS). MethodsThe primary efficacy and safety outcomes were the in-stent restenosis (ISR) rate and post-procedural stroke or death within one month. ResultsAtlas stents were deployed using the Gateway catheter and microcatheter in 19 (57.6 %) and 14 (42.4 %) procedures, respectively. Follow-up imaging data were available for 26 patients; the incidence of ISR was 15.4 %, and the ISR rate was higher, though not significantly, in the microcatheter group than in the Gateway group (30.0% vs. 6.25 %, P = .39). Clinical follow-up data were available for 30 patients; the post-procedural stroke rate was 3.3 % within one month and 13.3 % from one month to one year. The post-procedural stroke rate within one month was higher, though not significantly, in the microcatheter group than in the Gateway group (7.7% vs. 0 %, P = .43). The Gateway group had a significantly lower rate of post-procedural stroke in the same territory than that of the microcatheter group (0% vs. 30.8 %, P = .026). A higher incidence of residual stenosis <30 % was found in the non-ISR group than in the ISR group (72.2% vs. 0 %, P = .014). ConclusionsThis study provides preliminary evidence that the Atlas stent is safe and effective for IS treatment. The use of the Gateway catheter to deliver the Atlas stent appears to be safer than using microcatheter. The incidence of ISR may be related to the degree of the residual stenosis.

Abstract 044: Single‐Step Intracranial Angioplasty followed by Atlas Stent Deployment Through Mini Trek Rx Balloon

Introduction The current FDA approved intracranial stent delivery system requires a multi‐step deployment involving the use of exchange length microwire (ELW), typically 0.014‐inch 300 cm wire, to navigate the balloon catheter, which is then exchanged, after performing the angioplasty, over the ELW to a 0.017’ microcatheter that is used to deploy the intracranial stent. Herein, we describe a single‐step approach to deploy Neuroform Atlas stent (Stryker Neurovascular, Fremont, CA) which is a hybrid laser‐cut, nitinol self‐expanding stent without the need for ELW or lesion re‐access using MINI TREK RX (Abbott Vascular, Inc., Santa Clara, CA, USA) semi compliant balloon adapted from cardiovascular literature which showed a pre‐dilation angioplasty capability in coronary stenotic lesions. Methods We performed a retrospective review of prospectively maintained mechanical thrombectomy (MT) databases of 2 comprehensive stroke centers between November 2020, and May 2023. The inclusion criteria were consecutive large vessel occlusion stroke patients in whom single step MINI TREK RX balloon angioplasty followed by Neuroform Atlas intracranial stent deployment was performed without using ELW (Figure‐1). There was no restriction on time from last known well (TLKW) to MT. During the standard mechanical thrombectomy procedure, intracranial atherosclerotic disease/ significant stenotic lesion was suspected by immediate re‐occlusion/ persistent occlusion following at least 1 thrombectomy pass. This is followed by pursuing intracranial angioplasty and stent placement as a rescue recanalization measure. The primary outcome was successful reperfusion defined as a Modified Treatment in Cerebral Ischemia (mTICI) score of 2b or greater at the end of the procedure. Secondary outcomes included NIH Stroke Scale (NIHSS) at 24 hours, NIHSS at discharge, median modified Rankin Scale (mRS) score at discharge and at 90‐day follow‐up. Safety measures included rates of symptomatic intracranial hemorrhage (sICH) and mortality at 90 days. Results Among 9 patients who met our criteria, the median age was 63 (51‐69.5) years and 55.6% were females. Most patients had left middle cerebral artery‐ M1 occlusion (66.7%) and one third received thrombolytics (33.3%). All patients underwent the single‐step approach and achieved successful reperfusion (m TICI 2b‐3) with 2 median number of passes. The median NIHSS was reduced from 13.5 (8.5‐17.5) at baseline to 4 (1‐16.5) at discharge. In addition, median mRS was 1 (1‐3.5) at discharge and 3 (3‐4) at 90 days. None of the patients included in this series had sICH while only one patient with basilar artery occlusion underwent ventriculostomy during hospital stay and was sedated/intubated and died. Conclusion This preliminary experience showed technical feasibility and success of using single‐ step to deploy Neuroform Atlas stent after performing angioplasty using MINI TREK RX without the need for ELW or lesion re‐access. Prospective studies with larger sample size and long‐term clinical follow‐up are warranted to confirm these results.

Use of the neuroform atlas for stenting of intracranial atherosclerotic disease: Clinical and angiographic outcomes.

Intracranial atherosclerotic disease (ICAD) is a potential cause of ischemic stroke. Treatment of ICAD can include intracranial stenting. There are specifically designed stents for this use-case; however, less is known about the off-label use of the Neuroform Atlas stent. In this study, we describe the outcomes of the Neuroform Atlas stent for treatment of ICAD. Adult patients with symptomatic ICAD failing best medical treatment undergoing elective intracranial stenting using the Neuroform Atlas stent between November 2018 and March 2021 were included. Patient demographics, procedure-related details and clinical and imaging outcomes were analyzed. Eighteen patients met the inclusion criteria, with a mean follow-up duration of 9.6 ± 6.8 (standard deviation) months. There were two procedure-related mortalities (one massive intracranial hemorrhage and one groin site complication with sepsis). Fifteen patients were alive at the 6-month follow-up, all with satisfactory stent patency on follow-up imaging without any new ischemic events. Modified Rankin Scale at latest follow-up was 1.9 (interquartile range 5). In this single-center consecutive series, intracranial stenting with the Neuroform Atlas stent was a safe and effective treatment for symptomatic ICAD patients failing best medical management.

Comparative analysis of long term effectiveness of Neuroform Atlas stent versus low profile visualized intraluminal stent/Woven EndoBridge devices in treatment of wide necked intracranial aneurysms

BackgroundWe compared the outcomes of wide necked aneurysms (WNA) treated with the Neuroform Atlas with those treated with the low profile visualized intraluminal stent (LVIS) or the Woven EndoBridge (WEB).MethodsObjective,...

Silent Embolic Infarction after Neuroform Atlas Stent-Assisted Coiling of Unruptured Intracranial Aneurysms.

There is still controversy regarding whether neck remodeling stent affects the occurrence of silent embolic infarction (SEI) after aneurysm coiling. Thus, the aim of the present study is to investigate the incidence of SEI after stent-assisted coiling (SAC) using Neuroform Atlas Stent (NAS) and possible risk factors. This study also includes a comparison with simple coiling group during the same period to estimate the impact of NAS on the occurrence of SEI. This study included a total of 96 unruptured intracranial aneurysms in 96 patients treated with SAC using NAS. Correlations of demographic data, aneurysm characteristics, and angiographic parameters with properties of SEI were analyzed. The incidence and characteristics of SEI were investigated in 28 patients who underwent simple coiling during the same period, and the results were compared with the SAC group. In the diffusion-weighted imaging obtained on the 1st day after SAC, a total of 106 SEI lesions were observed in 48 (50%) of 96 patients. Of these 48 patients, 38 (79.2%) had 1-3 lesions. Of 106 lesions, 74 (69.8%) had a diameter less than 3 mm. SEI occurred more frequently in older patients (≥60 years, p=0.013). The volume of SEI was found to be significantly increased in older age (≥60 years, p=0.032), hypertension (p=0.036), and aneurysm size ≥5 mm (p=0.047). The incidence and mean volume of SEI in the SAC group (n=96) were similar to those of the simple coiling group (n=28) during the same period. SEIs are common after NAS-assisted coiling. Their incidence in SAC was comparable to that in simple coiling. They occurred more frequently at an older age. Therefore, the use of NAS in the treatment of unruptured intracranial aneurysm does not seem to be associated with an increased risk of thromboembolic events if antiplatelet premedication has been performed well.

Use of the Neuroform Atlas stent for wide-necked cerebral aneurysms

To investigate the effect and safety of the Neuroform Atlas (NFA) stent in stent-assisted coiling of wide-necked intracranial aneurysms, patients with wide-necked intracranial aneurysms were retrospectively enrolled and treated with the NFA stent-assisted coiling. The modified Rankin scale (mRS) grades and Raymond grades were used to assess the clinical outcomes and aneurysm occlusion degrees, respectively, after embolization and at follow-up. Totally, 122 patients were enrolled with 129 wide-necked aneurysms, and forty-nine (40.2%) patients experienced subarachnoid hemorrhage. A total of 134 NFA stents were deployed in all patients. Immediately after endovascular embolization, the Raymond grade was I in 112 (86.8%), II in 8 (6.2%), and III in 9 (7.0%). Complications occurred in 7 (5.7%) patients, including stent displacement in 2 (1.6%) patients, thrombosis and cerebral infarction in 4 (3.3%), and death in 1 (0.8%). Clinical follow-up was performed in 113 (92.6%) patients 6–30 (mean 21) months after embolization, with the mRS grade 0 in 99 (87.6%) patients, 1 in 7 (6.2%), 2 in 5 (4.4%), and 3 in 2 (1.8%). Good prognosis (mRS ≤ 2) was achieved in 111 (98.2%) patients while poor prognosis (mRS > 2) in two (1.8%). Digital subtraction angiography was conducted in 98 (80.3%) patients with 104 (80.6%) aneurysms 6–30 (mean 21) months after embolization. The Raymond grade was grade I in 94 (90.4%) aneurysms, II in 4 (3.8%), and III in 6 (5.8%). Compared with the Raymond grades immediately after embolization, 93 (89.4%) aneurysms disappeared, 9 (8.7%) remained unchanged in the occlusion status, and 2 (1.9%) were recurrent. In conclusion, the NFA stent may have a high aneurysm occlusion rate and a low complication rate in assisting coiling of wide-necked intracranial aneurysms even though further studies are necessary to prove this.

Embolization of unruptured wide-necked aneurysms at the MCA bifurcation using the Neuroform atlas stent-assisted coiling: a two-center retrospective study.

The management of middle cerebral artery (MCA) aneurysms remains a controversial topic, and MCA aneurysms have traditionally been treated primarily by surgical clipping. The Neuroform Atlas Stent™ (NAS, available from Stryker Neurovascular, Fremont, California) represents the latest generation of intracranial stents with improved stent delivery system capabilities. This study aims to investigate the safety, feasibility and efficacy exhibited by NAS in treating unruptured aneurysms at the MCA bifurcation. This was a two-center retrospective study involving 42 patients with unruptured wide-necked aneurysms (WNAs) of the MCA treated with the NAS from October 2020 to July 2022. The stent was used to treat 42 cases of unruptured WNA at the MCA bifurcation. Endovascular treatment techniques had a 100% success rate. Immediate postoperative angiography found complete aneurysm occlusion in 34 patients (80.9%) (mRRC 1), neck remnant in 7 patients (16.7%) (mRRC 2), and residual aneurysm in 1 patient (2.4%) (mRRC 3). The thromboembolic complication rate was 2.4% (1/42). The follow-up period was 8.7 months on average (3-16 months). The last angiographic follow-up results revealed complete aneurysm occlusion in 39 patients (92.9%) (mRRC 1), neck remnant in 3 (7.1%) patients (mRRC 2), no aneurysm recanalization or recurrence, and no cases of stent intimal hyperplasia. During the latest clinical follow-up, all patients had an mRS score of 0. Our study demonstrates that the NAS can be applied to treat unruptured WNAs at the MCA bifurcation with favorable safety, feasibility, and efficacy.

Novel technique of stent placement via gateway balloon in intracranial atherosclerosis-associated large vessel occlusion.

Neuroform Atlas stent can be deployed directly via gateway balloon for angioplasty and stent placement without the need for exchange maneuver required for Wingspan stent use. We present our initial experience of this strategy in intracranial atherosclerosis-associated large vessel occlusions. Patients were identified through mechanical thrombectomy (MT) database from January 2020 to June 2022 at our institutions. Due to reocclusion or impending occlusion, rescue angioplasty with stent placement was performed after initial standard MT. Primary outcomes were good angiographic recanalization with modified thrombolysis in cerebral infarction (mTICI) score of 2b-3, rate of intracranial hemorrhage (ICH), and favorable functional outcome at 3months, that is, modified Rankin Scale (mRS) score of 0-3. We identified 22 patients treated using this technique. Among those, 11 were females with their average age at 66years (range: 52-85). Initial median National Institute of Health Stroke Scale score was 11 (range: 5-30) and all patients received loading doses of aspirin and P2Y₁₂ inhibitor. After performing submaximal angioplasty and Neuroform Atlas stent deployment through the gateway balloon, we achieved final mTICI of 2b-3 in 20 (90%) patients. One patient had ICH post-op that was asymptomatic. Eight (36%) patients had mRS of 0-3 at 90days. Our preliminary experience suggests possible safety and feasibility of deploying Neuroform Atlas stent through a compatible Gateway balloon microcatheter without the need for ICH-associated microcatheter exchange. Further studies with long-term clinical and angiographic follow-up are warranted to corroborate our initial findings.

Expanded range of indications for Neuroform Atlas stent in the treatment of very small, wide-necked cerebral aneurysms

The purpose of this study was to investigate the range of indications for using the Neuroform Atlas stent. Between 2016 and 2020, we treated 20 females and 5 males for aneurysms with a diameter of less than 3 mm and an aspect ratio less than 1.5. The diameter of the parent arteries varied from 1.1 mm to 4.5 mm. There were 13 ruptured and 12 unruptured aneurysms. Double stent-assisted coiling was performed in 14 cases, and single stent-assisted coiling was performed in 11 cases. After deployment, the morphology of the Neuroform Atlas stents was analyzed in tapered or Y-shaped silicone tubes that simulated parent arteries. Radiological results were assessed 7 months and 2 years after the intervention using the Raymond-Roy scale. Clinical outcome was assessed 1 year after the intervention using the modified Rankin score. There were three fatal outcomes. One aneurysm was recoiled. The rate of class I aneurysm occlusion was registered in 21 patients at the last follow-up. At the end of the clinical follow-up period, a favorable outcome (modified Rankin scale 0 –1) was registered in nine patients with ruptured aneurysms. An analysis of the morphology of the stents deployed in the silicone tubes provided an explanation for the stability of the coil mass in the treated aneurysms. Our results suggest that the range of indications for use of the Neuroform Atlas stent can be expanded beyond the present range with regard to the diameter of the parent vessels and size of the aneurysms.

Additional rescue stenting with Neuroform Atlas stents during stent-assisted coiling of saccular aneurysms

ObjectiveOverlapping stenting is sometimes attempted during endovascular treatment of cerebral aneurysm as a rescue for coil herniation, stent mal-positioning, or in-stent thrombosis. We retrospectively evaluated the efficacy and safety of additional rescue stenting (ARS) in telescoping fashion with Neuroform Atlas stent (NAS) during stent-assisted coiling of saccular aneurysms. MethodsWe collected clinical and radiological data of patients with saccular aneurysms treated with ARS using NASs between March 2018 and December 2021. Y or X-stent-assisted coiling technique was excluded. ResultsEighteen unruptured and 5 ruptured aneurysms in 23 patients were treated with ARS using NASs. Sizes of aneurysms ranged from 2.0 mm to 10.0 mm (mean: 5.0 mm). Immediate angiographic results were complete occlusion in 11 aneurysms, residual neck in 4 aneurysms, and residual sac in 8 aneurysms. Peri-operative morbidity was 4.3 %. Nineteen of 23 patients underwent follow-up conventional angiography (mean, 9.9 months). Results showed progressive occlusion in 10 (52.6 %) cases and asymptomatic in-stent stenosis in 3 (15.8 %) cases. At the end of the observation period (mean, 17.4 months), all 18 patients without subarachnoid hemorrhage had excellent clinical outcomes (mRS of 0), except one (mRS of 1). Of five patients with subarachnoid hemorrhage, four had a favorable outcome (mRS of 0–1), while the other one was dependent (mRS of 4). ConclusionIn this report on 23 patients, ARS with NASs for treating saccular aneurysms showed good technical safety with favorable clinical and angiographic outcomes. However, delayed in-stent stenosis was not uncommon. Thus, regular imaging follow-up is required.

Need for Y-stenting in stent-assisted coiling of wide-neck bifurcation aneurysms

Background and PurposeStent-assisted coiling of wide neck bifurcation aneurysms in the anterior communicating segment and basilar tip region can be performed with varying stent configurations, including single stenting or Y-stenting. Y-stenting requires two stents and thus incurs greater cost and procedural complexity than single-stent constructs. The influence of first stent type on the need for Y-stenting remains unknown. Materials and MethodsClinical and angiographic data were retrospectively obtained for patients that underwent stent-assisted coiling for basilar tip or anterior communicating aneurysms at a high-volume center. Patients were included in this study if stent-assisted coiling was performed using Neuroform Atlas or LVIS Jr stents. A multivariate binary logistic regression was performed to measure the influence of first stent type on the need for Y-stenting. ResultsStent-assisted coiling was used to treat 82 aneurysms in 81 patients during the study period, and Y-stenting was performed in 18.3% (15/82) of cases. In multivariate logistic regression analysis, use of LVIS Jr. as the first stent did not significantly influence the need for subsequent Y-stenting after controlling for aneurysm morphology (OR 0.65, 95% CI 0.18–2.43). ConclusionControlling for aneurysm morphology and location, the use of Y-stenting for stent-assisted coiling was not independently influenced by the choice of LVIS Jr or Neuroform Atlas as the first stent. A larger cohort may reveal differences between these two stents, particularly for aneurysms with large neck sizes.

Nitinol in Medical Devices: Not so Innocuous (P3-5.019)

<h3>Objective:</h3> We report two cases of delayed leukoencephalopathy (DLE) secondary to aneurysmal intracranial stenting and a middle ear prosthesis, both made of a nickel-titanium alloy (nitinol). <h3>Background:</h3> Nitinol is widely used in medical device manufacturing due to its favorable physicochemical properties: shape memory, biocompatibility, superelasticity, and corrosion resistance. <h3>Design/Methods:</h3> Two case reports. <h3>Results:</h3> A 36-year-old woman with a history of ankylosing spondylitis presented with headache and visual distortion. She was found to have an intracranial aneurysm that was repaired with the Neuroform Atlas Stent System. Five weeks later, she acutely developed a fluctuating right sensorimotor deficit. Magnetic resonance imaging (MRI) of the brain showed small regions of T2 hyperintensity with stippled enhancement in the right frontal lobe along the superior frontal sulcus and the white matter of the left parietal and occipital lobes. Another 72-year-old woman with a history of otosclerosis, status post-surgery with eclipse piston prosthesis, presented with right trigeminal neuralgia. A brain MRI showed a right paraclinoid meningioma and three upper cervical cord lesions on sagittal slices. She received radiotherapy with improvement. Seven weeks later, she developed hypersomnolence, vomiting, diplopia, and ataxia. Brain MRI demonstrated an interval appearance of multifocal and bilateral ring-enhancing lesions in the cerebellum, pons, and the right midbrain. Both patients had extensive and unremarkable serum, CSF, vascular and spine imaging, and malignancy workup. A manufacturer review of both devices revealed that they were made of nitinol. <h3>Conclusions:</h3> Titanium and nitinol are less well-known as allergens than nickel. In ionic form, they act as haptens, bonding to native proteins and stimulating the immune system 1) immediately with mastocytes and basophils degranulation (Type I) or 2) in a delayed, type IV cellular hypersensitivity that might present in the brain and spinal cord as a demyelinating disease. We hope to increase clinician awareness of nitinol-induced DLE, which could be easily misdiagnosed. <b>Disclosure:</b> Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bayer. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genentech. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Celgene/BMS. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genzyme. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Merck Serono. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Teva Neurosciences. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TG Therapeutics. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Teva. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Novartis. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Genentech. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for BMS. The institution of Dr. Zabad has received research support from Adamas. The institution of Dr. Zabad has received research support from Biogen. The institution of Dr. Zabad has received research support from Novartis. The institution of Dr. Zabad has received research support from Sun Pharma. The institution of Dr. Zabad has received research support from Parexel &amp; MedDay Pharmaceuticals. Dr. Solis has nothing to disclose. Dr. Venegas has nothing to disclose. Dr. Dennis has nothing to disclose. Dr. Piccione has nothing to disclose. Dr. Westerhuis has nothing to disclose. Dr. Arcot Jayagopal has nothing to disclose.

563 Post-Approval Three Year Outcomes Study of the Neuroform Atlas Stent for Treatment of Wide-Neck Intracranial Aneurysms

INTRODUCTION: Favorable safety and effectiveness outcomes were presented previously for the Neuroform Atlas Stent following the completion of its pre-market study (ATLAS trial [Safety and Effectiveness of the Treatment of Wide Neck, Saccular, Intracranial Aneurysms with the Neuroform Atlas Stent System]) in anterior and posterior cohorts. METHODS: The ATLAS post-approval study was a multicenter, prospective, single-arm, open-label study of wide neck (neck ≥ 4mm or dome-to-neck ratio &lt;2) intracranial aneurysms in the anterior and posterior circulations treated with the Neuroform Atlas Stent and approved coils. The primary effectiveness endpoint was complete occlusion (Raymond-Roy class 1) on angiography in the absence of retreatment or significant parent artery stenosis (&gt;50%) through 3 years post-procedure. The primary safety endpoint was occurrence of major stroke, ipsilateral stroke, or neurological death through 3 years post-procedure. Independent adjudication of primary endpoint outcomes was completed by an Imaging Core Laboratory and Clinical Events Committee. RESULTS: A total of 146 anterior and 101 posterior cohort subjects from the pre-market study population were enrolled for continued follow-up. Subject demographics and aneurysm anatomy were representative of pivotal trial findings. For anterior subjects, the mean aneurysm size was 6.1±2.4 mm and the mean dome-to-neck ratio was 1.2±0.3 mm. In posterior subjects, the mean aneurysm size was 7±2.7 mm and the mean dome-to-neck ratio was 1.2±0.4 mm. At 3-year follow-up, the percent of target aneurysm progressive occlusion rated the same or better was 84.4% (95% CI, 67.2% - 94.7%) of anterior subjects and 90.0% (95% CI, 73.5% - 97.9%) of posterior subjects. A primary safety event was reported in 0.7% (1/146) of anterior and 1.0% (1/101) of posterior subjects, respectively, with no neurological deaths. CONCLUSIONS: The results of the ATLAS post-approval study demonstrate durable treatment effectiveness and favorable safety outcomes.